membrane fouling Articles
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The removal of typical pollutants in secondary effluent by the combined process of powdered activated carbon–ultrafiltration
This paper focused on the effects of powdered activated carbon (PAC) dosage on ultrafiltration (UF) membrane flux caused by natural organic matter (NOM). Three model foulants, humic acid (HA), bovine serum albumin (BSA) and sodium alginate (SA), were adopted to represent different NOM fractions in secondary effluent treated by the combined process of PAC-UF. Moreover, the membrane fouling ...
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Membrane chemical cleaning: from art to science
Membrane chemical cleaning is an integral part of operation for micro- and ultrafiltration systems in the water industry and has significant impact on process operations. However, this issue has not been adequately addressed primarily for two reasons: 1) cleaning protocols are typically recommended from membrane manufacturers and some cleaners are proprietary; 2) the issues of membrane fouling ...
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Flocs' re-growth characteristics in circulation coagulation–membrane filtration process
Membrane fouling can be significantly mitigated through circulating coagulation, floc breakage and re-growth under appropriate conditions. In this study, unified membrane filtration index (UMFI) was adopted to analyze the membrane fouling. The effect of circulating coagulation pretreatment on both flocs' average diameter and membrane fouling were investigated under different ...
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Hybrid TiO2 photocatalytic oxidation and ultrafiltration for humic acid removal and membrane fouling control
Hybrid UV/TiO2 photocatalytic oxidation (PCO) and ultrafiltration (UF) process (PCO-UF) were used to remove humic acid (HA) and control membrane fouling. The PCO-UF process showed advantages in terms of higher removal rate of HA, higher permeate flux and less membrane fouling over UF alone and PCO alone on HA removal and membrane fouling control. Membrane material and pH of feed water were shown ...
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Influence of membrane properties on physically reversible and irreversible fouling in membrane bioreactors
This study aimed to examine the impact of membrane properties on membrane fouling in membrane bioreactor (MBR). Membrane fouling was divided into two categories: physically reversible and irreversible fouling. Membrane properties related to each type of membrane fouling were investigated separately. Five microfiltration (MF) and one ultrafiltration (UF) membranes with different properties (pore ...
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Membrane fouling mitigation by activated carbon addition in activated sludge filtration
Activated carbon (AC) was added into the activated sludge to alleviate membrane fouling during sludge microfiltration. The fouling mitigation profiles were evaluated at different AC sizes and doses by a single-fibre microfiltration system. It was found that the granular AC added in the sludge suspension can absorb the organic substances in the sludge in a certain level, including biopolymer ...
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The impact of anionic polyacrylamide (APAM) on ultrafiltration efficiency in flocculation-ultrafiltration process
With the purpose of improving the ultrafiltration (UF) efficiency, anionic polyacrylamide (APAM) has been used as a coagulant aid in the flocculation-UF process. In this study, the impact of APAM on UF efficiency has been investigated with regard to membrane fouling, membrane cleaning and effluent quality. The results indicated that the optimal dosage of APAM had positive impacts on membrane ...
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Impact of magnetic ion exchange resin pretreatment on alleviating UF membrane fouling
The purpose of this study is to undestand the effect and mechanism of preventing ultrafiltration(UF) membrane fouling by using magnetic ion exchange resin (MIEX®) in terms of fractional compent and molecular weight of NOM. In the experiment, pretreatment decreasing trans-membrane pressure and preventing membrane fouling were studied. The result showed: when the MIEX® dosage reached 800 bed volume ...
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Correlations of relevant membrane foulants with UF membrane fouling in different waters
Membrane fouling is one of the main obstacles that restricts the more widespread application of UF membrane in both drinking water treatment and reclamation of WWTP secondary effluent. Numerous researchers and engineers have devoted to overcome the membrane fouling in the past decade. However, for better addressing the fouling issue, it is necessary to identify the major membrane foulants in ...
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Effects of mixed liquor pH on membrane fouling and micro-pollutant removals in membrane bioreactors for municipal landfill leachate treatment
This research investigated the membrane fouling and micro-pollutant removals in treatment of municipal landfill leachate at various pH levels (i.e. 5.5, 6.5, 7.5, and 8.5) using membrane bioreactors. The findings revealed that membrane fouling was influenced by the pH level of mixed liquor, with pH 5.5 exhibiting the most severe membrane fouling. At pH 5.5, proteins and carbohydrates were ...
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Optimization of aeration conditions in the hybrid process of coagulation-ultrafiltration with air sparging
To optimize the aeration conditions in the hybrid process of coagulation-ultrafiltration with air sparging, a series of air flow rates under continuous and intermittent sparging were investigated. The water quality characteristics that surrounded membranes, bubble characteristics, fouling resistances, and energy consumption under different aeration conditions were analyzed. The results showed ...
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Effects of tannic acid on membrane fouling and membrane cleaning in forward osmosis
The fouling behavior during forward osmosis (FO) was investigated. Tannic acid was used as a model organic foulant for natural organic matter analysis since the main characteristics are similar, and calcium ions were added at different concentrations to explore the anti-pollution capability of FO membranes. The initial permeate flux and calcium ions strength were varied in different operating ...
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Membrane fouling in the nanofiltration of landfill leachate and its impact on trace contaminant removal
Nanofiltration (NF) is an attractive option for the treatment of landfill leachate. However, membrane fouling can be a major obstacle in the implementation of this technology. In this study, bench-scale filtration experiments were carried out to study the fouling behaviour during the NF of a synthetic landfill leachate. The results indicate that calcium in combination with organic matter could ...
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Considerations for the design and operation of a membrane bioreactor
This paper reviews recent advances in research focusing on the design and operation of a membrane bioreactor and including methodologies for determining the timing for hydraulic and sludge retention, sludge concentration optimisation, the removal of nitrogen and phosphorus, membrane fouling control, and the analysis of processing economics.Keywords: membrane bioreactors, activated sludge, ...
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Membrane foulants and fouling mechanisms in microfiltration and ultrafiltration of an activated sludge effluent
Membrane fouling in microfiltration (MF) and ultrafiltration (UF) of an activated sludge (AS) effluent was investigated. It was found that the major membrane foulants were polysaccharides, proteins, polysaccharide-like and protein-like materials and humic substances. MF fouling by the raw effluent was governed by pore adsorption of particles smaller than the pores during the first 30 minutes of ...
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Membrane fouling caused by sub-micron particles in a mixed liquor suspension of an MBR
Membrane fouling needs to be mitigated for widespread use of membrane bioreactors (MBRs). It has been pointed out that particles with small sizes found in supernatants (sub-micron particles) of mixed liquor suspensions of MBRs are important in the evolution of membrane fouling of this technology. However, information on characteristics of sub-micron particles in MBRs is still insufficient. In ...
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Performance comparison of rotating disk ultrafiltration membrane module, a high shear device with cross–flow module
Apart from plenty of advantages, the main disadvantage of ultrafiltration is rapid flux decay due to concentration polarisation and membrane fouling. The purpose of this work is to overcome this problem employing shear enhanced membrane filtration technique. To accomplish this, two different membrane modules were used; one was a standard cross–flow membrane module and the other one was the ...
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Evaluation of the importance of various operating and sludge property parameters to the fouling of membrane bioreactors
A single-fibre microfiltration system was employed to investigate the importance of various operating and sludge property parameters to the membrane fouling during sludge filtration. The sludge was obtained from a submerged membrane bioreactor (SMBR). A series of comparative and correlative filtration and fouling tests were conducted on the influence of the operating variables, sludge properties ...
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Membrane fouling
The Problem: Membrane water treatment is costly and complex due to the systems required to mitigate membrane fouling. Membranes have, therefore, been relegated to high value applications such as desalination and ultra-pure water needs. The systems used to mitigate fouling have a history of underperformance and high cost. EconoPure Solution: EconoPure has developed a low-fouling nanofiltration ...
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Effect of low dosages of powdered activated carbon on membrane bioreactor performance
Previous research has demonstrated that powdered activated carbon (PAC), when applied at very low dosages and long SRTs, reduces membrane fouling in membrane bioreactors (MBRs). This effect was related to the formation of stronger sludge flocs, which are less sensitive to shear. In this contribution the long-term effect of PAC addition was studied by running two parallel MBRs on sewage. To one of ...
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